Electrical translating apparatus



June 13, 1933. J SQRENSEN r AL 1,914,220

ELECTRI CAL TRANSLATING APPARATUS Filed June 23, 1930' 3 Sheets-Sheet l RPCZ hpaz A 21 IILIP H J femnzzfal Relay as I.

Input TA 1 2A INVENTORS 7 0L006! fikJjsorenscr q J 1933- A. J. SORENSEN ET AL 1,914,220

ELECTRICAL TRANSLATING APPARATUS Filed June 23, 1930 5 Sheets-Sheet 2 Input 18 A Fig. 5. 55 1 Relay 4.21 flffemntial Relay 2 F 5 I INVENTOR-S w B Zog/ ,20 A I sorensqnf June 13, 1933. A. J. ,SORENSEN El AL 1,914,220

ELECTRICAL TRANSLATING APPARATUS Filed June 23, 1930 3 Sheets-Sheet 3 55% Differential Relay Fig. 6.

INVENTORS WWW? Patented June 13, 1933 UNITED STATES PATENT OFFICE ANDREW I. somsm, 01' PITTSBURGH, AND PHILIP H. DO'WLING, OI SWISSVALE, I PENNSYLVANIA. ASSIGNOBS TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISS- VALR PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA ELECTRICAL TBANSLATING APPARATUS Application filed June 88, 1980. Serial No. 462,994.

Our' invention relates to electrical translating apparatus, and particularly to apparatus comprising an input circuit at t mes supplied with current and means for at times 4| sup lying a load with current in accordance wi the current flowing in the input circuit.

More particularly our present invention relates to electrical translating apparatus of the type described in which two output circuits are su plied with currents which are normally be anced in their effect upon the load, but which are varied in oppos1te senses, that is, one is increased while the other is decreased, in response to changes in the current supplied to the input circuit.

We will describe several forms of electrical translating apparatus embodying our invention and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a diagrammatic view showing one form of electrical translating apparatus embodying our invention. Figs. 2 and 3 are dia rammatic views showing modified forms electrical translating apparatus embodying our invention. Figs. 4 and 5 are detailed views showing two modifications of a portion of the a paratus illustrated in Fig. 3 and also embodying our invention. Fig. 6 is 8. diagrammatic view showing still another form of electrical translating apparatus embodying our invention.

Similar reference characters refer to similar parts in each of-the several views.

Referring first to Fi 1, the reference characters T and T designate magnetic amplifiers each comprising an input circuit, and an output circuit in which the flow of current is controlled in accordance with the current supplied to the input circuit. As here shown, each of the magnetic amplifiers T and T is of the bridge type, disclosed and claimed in a co nding ap lication for Letters Patent of t e United tates, Serial No. 426,564 filed Februa 7 1930, by Andrew J. Sorensen, for electrical translating apparatus. Referring particularly to amplifier T, this device comprises two magnetizable cores 1 and 5 of the usual shell type. Thus 50 core 1 comprises two outer legs 2 and 4 carrying windings 9 and 10, respectively. The middle leg 3 of core 1 carries a biasing winding 11 and an input winding 12. The core 5 comprises two outer legs 6 and 8 carrying windings 13 and 14, respectively, and a middle leg 7 provided with a biasing .winding 15 and an input winding 16. Alternating flux is supplied to the cores 1 and 5 by windings 9, 10, 13 and 14, which are connected with a suitable source of alternating current, here shown as a generator G. As will be apparent from an inspection of the drawings, the windings 9, 10, 13 and 14 are connected together in a closed circuit to form a bridge across two opposite corners of which is connected the generator G. Across the other corners of the bridge we connect a load, which as here shown, is one winding of a differential device illustrated as a polarized differential relay K. Windin 20 is connected with the output circuit 0 the magnetic amplifier T, through a rectifier R, and a condenser 19 is connected in parallel with the Winding 20. Furthermore, a condenser 18 may be inserted in series with the generator G across the bridge of magnetic amplifier T. The magnetic amplifer T is similar to amplifier T and comprises a core 1 having two outer legs 2 and 4 carrying windings 9 and 10 and a middle leg 3 provided with a biasing winding 11 and an input winding 12. The amplifier T also comprises a core 5 having outer legs 6 and 8 provided with windings 13 and 14, respectively. The middle leg? of core 5 is provided with a biasing Winding 15 and an input winding 16 The windings 9 10 13 and 14 of amplifier T are connected together to form a bridge across opposite corners of which the generator G is connected in series with condenser 18. The other two corners of this bridge are connected through a rectifier R with a second winding .20 of the differential relay K. A condenser 19 is connected across winding 20.

The windings located on the outer legs of the cores of the magnetic amplifiers are so disposed and connected that the alternating fluxes created thereby in the corresponding cores are opposed in the middle legs of the cores so that the principal path of the alternating flux in these cores is through the outer legs and the outer magnetic circuit of the cores. The cores of the magnetic amplifiers are adjusted to optimum points on their characteristic curves by means of the biasing windings 11*, 15",-15 and 11 which are supplied with current in series from a suitab a source of energy, such as a battery 17.

The magnetic amplifiers T and T are controlled by a circuit including the input windings 12 16, 16 and 12. This input circuit may be supplied with current from any suitable source and the parts are so ad- 'usted that when the current in this circuit as its normal value, usually zero, the currents supplied to windings 20 and 20 of the differential relay K will be exactly balanced and under these conditions the contact 35 of the relay will assume a middle position. The magnetic amplifiers T and T may conveniently be adjusted to deliver output currents to the windings 20 and 20 in the absence of input current by proportioning the biasing windings 11 and 11 'to deliver a greater biasing flux than the biasing windin 15 and 15. With this adjustment, if t e amplifiers are otherwise balanced, the output circuits of the amplifiers will each deliver a current, the magnitude of which depends upon the amount of unbalance between the biasing fluxes in the two cores of the separate amplifiers.

When current is supplied to the input circuit, however, the flux created in the middle legs of the cores of the magnetic amplifiers vary the permeabilities of these cores and change the balances of the bridge circuits including the alternating current windings on the outer legs of these cores. The various parts will be so adjusted that when the input circuit is supplied with current of one polarity, the output current of one amplifier will be increased and the output current of the other amplifier will be decreased. For example, when current is supplied to the input circuit, the current supplied to winding 2O may be increased and the current supplied to winding 20 may be decreased. The net result is a destruction of the normal balance existing between the currents in these windings and the relay K is then operated to swing its contact 35 in one direction, as to the left. If, however, the input circuit is supplied with current of the other polarity, the current in the output circuit of amplifier T'- is decreased so that the current supplied to winding 20 of relay K is correspondingly decreased. This same change in the input current also causes the output current of amplifier T and hence the current supplied to winding 20 of relay K to be increased. The net result is an unbalance of the currents supplied to the differential relay K in the opposite direction, so that the contact 35 of thlS relay is swungto the right.

It should be observed that with this arrangementthe character of the current supplied to the load, here represented by the relay K, corresponds to the character of the current su plied to the input circuit. For example, i the input circuit is supplied with alternating current, the relay K is energized in such manner that the current predominates alternately in windings 20 and 20 and the contact 35 swings to and fro between its. two extreme positions. If, however, the current suppliedto the input circuit is ulsating unidirectional current, the relay will be. operated to one extreme position by each impulse of such current, and will return to its normal condition in which the currents in its windings are balanced each time the current in thecircuit returns to its normal value.

The input circuit may receive'its energy from any suitable source, but as here shown, the apparatus is employed to amplify train controlling currents received from the trackway in a system of automatic train control. For this pur ose, the rails 21 and 21' of a stretch of rai way track are divided by means of the usual insulated joints to form a track section EF. Train controlling current is supplied to the rails of this section by means of coding apparatus, here shown as a motor 28 constantly supplied with alternating current from a generator 27. The motor 28 comprises two code wheels 29 and 30 operating contacts 29 and 30' at difierent frequencies.

Alternating current supplied by the gen- .plied to section E-F over front contact 31 of this relay and contact 30" operated by code wheel 30. en traflic conditions in advance are unsafe, relay P is deenergized and alternating current is then supplied to the rails of section EF over contact 29" 0 rated by a code wheel 29. The rails of 51 section EF are thus supplied with alternatin current periodically interrupted at di erent frequencies depending upon which of the contacts operated by motor 28 is interposed between the rails of the section and the generator 27. The train controlling current thus supplied to the rails of the section is employed -to control governing means on a train and this may be accomplished by providing a train indicated diagrammatically at W with a receiver V located in advance of its forward axle and comprising two magnetizable cores 22 and .22 disposed in inductive relation with the track rails. The core 22 is provided with a winding 23 and the core 22" is provided with a winding 23, the wind ings 23 and 23 being connected in series in such manner that the voltages induced therein by train controlling currents flowing in opposite directions in the track rails are additive. The receiver V supplies current through a filter 24 and, a rectifier 25 to the primary of a trimsim'mer 26, thesecondary of which is connected in theinput circuit of the translating apparatus embodying our invention. With this arrangement, it will be apparent that each impulse of train controlling current in the track rails causes a cycle of alternating current inthe secondary of transformer 26 so that the input circuit of magnetic ampliers T and T are supplied with alternating current of the same frequency as the interruptions in the current supplied to the track rails. The contact of relay K is therefore swung to and fro between its extreme positions at the frequency ofthe interruptions in the train controlling current and this relay maybe utilized to control apparatus on the train which is selective y responsive. to the frequency of its operation in any well known manner. For example, the apparatus here shown, may control decoding apparatus including circuits which are selectively timed to electrical resonance at the frequencies of interruption of the trackway currents as disclosed and claimed in a copending application for Letters Patent of the United States. Serial No.

166,407, filed February 7, 1927, by Paul N.

Bossa-rt, for railway traffic controlling apparatus. The relay K of the present application would then correspond to the relay R of the Bossart application.

lVe have discovered that the condensers 19 and 19 perform important functions in increasing materially the sensitivity and overall amplification of the apparatus. The exact reason for this improved operation is not known, but apparently the condensers serve to by-pass a portion at least of the alternating component of the currents supplied to the load windings. It is also probable that the advantage obtained by these condensers is due partly to the fact that they balance a portion of the reactive impedances of the windings in the circuit, though the phenomenon is not one of simple resonance. because the operation of the apparatus is substantially unaffected by wide variations in the frequency of the electromotive force delivered by the generator G or in the frequencies of variations in the input circuits.

Referring now to Fig. 2. we have illustrated a modified form of our invention in which the magnetic amplifiers T and T each comprise only a single core. With this arrangement, the input circuit includes winding 12 on core 1 and winding 12 on core 1 and may be supplied with the controlling current from an suitable source. The biasing circuit supplie with current from battery 17 includes the biasing windings 11 and 11 The in series with windings 9 and 10 of amplifier T With this arrangement, it will be apparent that the currents supplied to winding 33 will be varied in accordance with the impedance of windings 9 and 10 and the current supplied to winding 33 will be varied in accordance with the impedance of windings wand 10. The two load windings 33 and 33 are a part of a differential device which might be the difierentialrelay K shown in Fig. 1, but is here shown as a transformer comprising a winding 34 arranged to supply current to a suitable load circuit in actordance with the difference between the currents in windings 33 and 33 \Ve prefer to arrange the windings 33 and 33 so that the fluxes created by currents in these windings are in opposition, and are balanced when no current is being supplied to the input circuit including windings 12 and 12 of magnetic amplifiers T and T When the input circuit is supplied'with current of one polarity, the current in the output circuit of one magnetic amplifier is increased and the current in the other magnetic amplifier is decreased. The net result is a destruction of the normal balance between the unidirectional currents in windings 33 and 83 and this change induces an electromotive force in the winding 34 which is available to supply current to a load connected with this winding. When the input circuit including windings 12 and 12 is supplied witn current of the opposite polarity. the operation of the two amplifiers T and T is just the reverse of that described above, and as a result, the currents in wind in gs 33 and 33 of transformer S become unbalanced in the other direction so that an electromotive force of the opposite polarity is induced in winding 34. It follows,.therefore, that if an alternating current is supplied to the input circuit of magnetic amplifiers T and T there will be induced in the winding 34, an alternating current of similar frequency and the parts mav be proportioned so that the current in winding 34 is many times greater than the current supplied to the input circuit. The apparatus shown in Fig. 2 may be utilized in the system illustratedin Fig. 1, but it should be particularly understood that the apparatus is not limited to such use.

It will be observed that in Fig. 2 a condenser 32 is connected across the input terminals of rectifier R and the condenser 32 is connected across the input terminals of rectifier B. These condensers increase the sensitivity of the apparatus embodying our invention, and accomplish the same functions as the condensers 19 and 19 shown in Fig. 1.

The apparatus shown in Fig. 3 is similar to that illustrated in Fig. 2, but the magnetic amplifiers T and '1 have their windings 9, 10, 9 and 10 connected in series with the generator G. Core 1 of amplifier T is provided with two output windings 36 and 37 located on outer legs 2 and 4 and these windings are connected in series across the input terminals of rectifier R which supplies current to one winding 20 of the difi'erential device, here shown as the relay K, described in connection with Fig. 1. In similar fashion, magnetic amplifier T is provided with two output windings 36 and 37 located on legs 2 and 4 respectively, and connectedwith the input terminal of rectifier R which suplies current to the other winding 20 of the differential device constituting the load. The windings connected with generator G therefore serve as primaries, and the output windings 36 37*, 36 and 37 serves as second-v aries, and the secondary induced voltages are controlled by current supplied to the input circuit, as will be apparent from the drawings.

Output terminals of like polarity of rectifiers R and R, as here sown, the negative terminals, are connected together with one terminal of a resistor 38. The other terminal of resistor 38 is connected with one terminal of each of the windings 20 and 20 of relay K and the free terminals of windings 20 and 20 are connected with the remaining terminals of rectifiers R and R respectively. The resistor 38 is introduced in the circuit to control the currents which How in the windings of the differential relay when the input circuit is supplied with current of normal value. For this purpose, current is supplied independently to resistor 38, and as here shown, this resistor is included in the biasin circuit supplied with current by battery 1% and including also biasing windings 11 and 11. The resistor 38 may be provided with an adjustable tap 39 so that the potential drop across the resistor may be varied. 1

When the current in the input circuit is zero, the electromotive forces induced in the output windings of the two amplifiers are equal, and the current supplied to windings 20 and 20 of relay K are also equal. The potential drop across resistor 38 opposes the currents supplied to relay windings 20 and 20 equally and by properly proportioning the parts, this normal, or no output current may be reduced to any desired value.

In Fig.4 we connect a resistor 40 directly in the biasing circuit including the battery 17 and windings 11 and'11'. By means of an adjustable tap 41 the ne ative output terminals of one rectifier, suc as R and the positive output terminal of the other rectifier R, are connected with a selected point on the resistor 40. One terminal of winding 20 is connected with the remaining output terminal of rectifier R and the other terminal of windin 20- is connected with one terminal of resistor 40. In similar manner, winding 20 of relay K is connected from the remaining output terminal of rectifier R to the free terminal of resistor 40. It will be seen that with this arrangement, rectifiers R and R aid in sendin current through the circuit including wi ings 20* and 20 and the resistor 40 inseries. The

otential drop across resistor 40 is 50 adusted that for the normal value of the input current, the current in the windings 20 and 20 through the circuit includin resistor 40 is held to the desired value. Un er these conditions, there is ordinarily no current flowing in thewire connected with tap 41. As soon, however, as the input current changes from its normal value, the currents delivered by the rectifiers R and R become unbalanced, and a difierence current flows through the wire connected with tap 41, and the resulting unbalance in the currents supplied to windings 20* and 20 operates relay K.

One advantage of the structure shown in I Fig. 4 is that by-adjustment of the tap 41, small differences between the outputs of the two magnetic amplifiers for normal values of the in ut current may be com nsated for so that t e currents in the win ings of the "differential device K may be exactly balanced. Another advantage is that the current'in the wire connected with tap 41 is the actual difference current, that is, the magniturle of this current is equal to the difference I between the magnitudes of the currents flowing in windings 20 and 20 and the apparatus thus lends itself to convenient observation and adjustment by. the use of proper meters inserted in this wire.

Referring now to Fi 5, the circuits for the windings of relay are similar to those shown in Fig. 3, except that the resistor 38 I is permanently connected in the biasing circuit and winding 20 is connected across a portion of this resistor in series with the output terminals of rectifier R while winding 20 of relay K is connected across an adj ustable portion of resistor 38 in series with the output terminals of rectifier R. With this arrangement, the adjustable tap 42 is manipulated until the currents in windings 20" and 20 are balanced at normal values of the input current. The potential drop across the resistor 38 caused by current supplied to the biasing circuit by battery 17 opposes the currents supplied to both windings 20 and 20 and holds them to any desired low value. One advantage of the structure here shown is that a single condenser 44 may be connected across terminals of like polarity oi the rectifiers R and R and when so arranged, performs all of the useful functions of the condensers 32 and 32 connected across the separate output circuits of the magnetic am lifiers as shown for example in Fig. 3. In a 1 other respects, the a paratus shown in Fig. 5 is similar to that diescribed in the preceding Figs. and will be understood without further explanation.

In the modification shown in Fig. 6, the output circuits are exactly the same as in Fig. 4 and the structure of the magnetic amplifiers is identical with that described in Fig. 3 but the windings 9 10*, 9 and 10, instead of being connected in series as in Fig. 3, are connected in a closed circuit to form a bridge, across two opposite corners of which is connected the generator G. A condenser 45 is connected across the remaining corners of this bridge and this condenser serves to increase the sensitivity of the apparatus in the same manner as the condensers connected in the output circuit and described in connection with the other views. It will be noted that in Fig. 6, as in Fig. 5, only one condenser is required.

It should be pointed out that we have described our invention as applied to the control of specific differential devices but that this feature is not essential. Apparatus embodying our invention could equally well be applied to the control of any oad comprising two windings adapted to be supplied with currents and responsive to the difference between such currents. It should also be pointed out that although we have described apparatus embodying our invention asapplied specifically to a train carr ed amplifier in any train control system, thls particular application is by way of illustration only, and is not to be construed as a limitation.

Attention should also be drawn to the fact that, as suggested in describing the apparatus shown in Fig. 1, the various forms of apparatus embodying our invention will operate upon input currents WlllCll are alternating or unidirectional.

It will be readily understood that the various modifications may be made in the alter nating current primary circuits supplied with current from generator G. For example, the condenser 18 shown in Fig. 1, may be employed in any of the other modifications.

Although we have herein shown and described only a few forms of electrical translating apparatus embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

' 1. In combination, a first set of four wind- 111%9 connected in a closed circuit to form a rst bridge, a second set of four windings connected in a closed circuit to form a second bridge, means for applying an alternati potential across'two op osite corners of can said bridge, a differential device comprising two load windings one connected across the remaining corners of each said bridge, and an input winding inductively related with at least one windin of each said set and operatmg when supp ied with current to vary the impedance of such windin in such manner as to change the relative va ue of the currents supplied to said load windings.

2. In combination, two magnetic amplifiers each comprising an input winding and an output circuit, an input circuit including both said input windings and operating when supplied with current to decrease the current in one said output circuit and to increase the current in the other output circuit, a differential device comprising two load windmgs, one receiving energy from each said output circuit, and two condensers one connected acrosseach said output circuit.

3. In comblnation, two magnetic amplifiers each comprising an input winding and an output clrcuit, an input circuit including both said input windings and operating when supplied with current to decrease the current in one said output .circuit and to increase the current in the other output circuit, a difierential device comprising two load windings, means including rectifiers for supplying en ergy from said two output circuits to said two load windings, respectively, and two condensers one connected across each said output circuit.

4. In combination, two magnetic amplifiers each comprising an input winding and an alternating current output winding, a differential device comprising two load windings one connected with each said output winding, two condensers one connected across each said output winding, and an. input circuit including both said input windings and operating when supplied with current to decrease the current supplied to one said load winding and to increase the current supplied to the other load winding.

5. In combination with a load comprising two windings, two rectifiers, means including two magnetic amplifiers for separately applying alternating electromotive forces across the input terminals of said rectifier-s, a conductor for connecting output terminals of one polarity of said rectifiers together, means for connecting the two windings of said load in series across the remaining output terminals of said rectifiers, and means for creating a unidirectional potential between said conductor and the common terminal of said load windings.

6. In combination, two magnetic amplifiers each having an input winding and an output circuit including a rectifier, an input circuit including both said in ut. windings and operating when supplie with current to 1ncrease the electromotive force applied to one said rectifier and to decrease the electromotive force applied to the other rectifier, a differential device having two load windings connected in series across terminals of one polarity of said rectifiers, a conductor connecting the remaining output terminals of said rectifiers, a resistor connected between said conductor and the common terminal of said load windings, and means for supplying current to said resistor to create therein a potential drop which op oses the electromotive forces applied to said load windings by said rectifiers.

7. In combination, two magnetic amplifiers each having an input winding, a biaslng winding, a primary winding supplied wit alternating current, and an output winding; an input circuit includin both said input windings and operating w en supplied wlth current to vary the electromotive forces induced in said output windings in opposite senses, a diflerential device having two load windings, two rectifiers for connecting said two load windings across said two output windings, respectively, and circuit including said biasing windings and operating to oppose the current supplied to both said load windings from said rectifiers.

8. In combination, two sources of alternating electromotive force, means for at times increasing the electromotive force of one source while decreasing the electromotive force of the other source, two rectifiers having their input terminals connected with said two sources, respectively, a'difierential device comprising two load windings, a resistor connected from one terminal of one load winding to one terminal of the other load winding, means for connecting the remaining terminals of said two load windings with output terminals of different polarity of said two rectifiers, respectively, means for ad- 'justably connecting the remainin output terminals of both said rectifiers wit a oint.

on said resistor, and means for supp ying current to said resistor to produce a potential drop across such resistor.

9. In combination, two sources of alternating electromotive force, means for at times increasing the electromotive force of one source while decreasing the electromotive force of the other source, two rectifiers having their input terminals connected with said two sources, respectively, a differential device comprising two load windings, a conductor connecting two output terminals of like polarity of said two rectifiers, respectively, a resistor having one terminal connected with said conductor, means for supplying current to said resistor to produce a potential drop across said resistor, means for connecting one said load winding from the remaining output terminal of one said rectifier to a point on said resistor, and means for connecting the other load winding from the remaining output terminal ofthe other rectifier to a oint on said resistor.

10. In com ination, two sources of alternating electromotive force, means for at times increasing the electromotive force of one source while decreasing the electromotive force of the other source, two rectifiers having their input terminals connected with said two sources, respectively, a difierential device comprising two load windings, a conductor connecting two output terminals of like polarity of said two rectifiers, respectively, a resistor having one terminal connected with said conductor, means for supplying current to said resistor to produce a potential drop across said resistor, means for connecting one said load winding from the remaining output terminal of one said rectifier to a point on said resistor, means for connecting the other load winding from the reo. maining output terminal of the other rectifier to a point on said resistor, and a condenser connected across said remaining output terminals of said two rectifiers.

11. In combination; two magnetic ampli fiers each comprising two primary windings, a secondary ing; means for connecting said four primary windings in a closed circuit to form a bridge, a source of alternating current connected acrosstwo opposite corners of said br'dge, a condenser connected across the other opposite corners of said bridge, an input circuit at times supplied with current and operating in response to a change in such current to increase the secondary induced electromotive force of one magnetic amplifier while decreasing the secondary induced electromotive force of the other magnetic amplifier, a differential device comprising two load windings and responsive tothe difference between the currents in said two load windin and means including rectifiers for connectlng said two load windings with the two output windings, respectively of said magnetic amplifiers.

In testimony whereof we affix our signatures.

ANDREW J. SORENSEN. PHILIP H. DOWLING.

winding and an output wind- 

